/*
 * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2013 Intel Corporation. All rights reserved.
 *
 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
 *
 * Other contributors:
 *   Robert O'Callahan <roc+@cs.cmu.edu>
 *   David Baron <dbaron@fas.harvard.edu>
 *   Christian Biesinger <cbiesinger@web.de>
 *   Randall Jesup <rjesup@wgate.com>
 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
 *   Josh Soref <timeless@mac.com>
 *   Boris Zbarsky <bzbarsky@mit.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Alternatively, the contents of this file may be used under the terms
 * of either the Mozilla Public License Version 1.1, found at
 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
 * (the "GPL"), in which case the provisions of the MPL or the GPL are
 * applicable instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of one of those two
 * licenses (the MPL or the GPL) and not to allow others to use your
 * version of this file under the LGPL, indicate your decision by
 * deletingthe provisions above and replace them with the notice and
 * other provisions required by the MPL or the GPL, as the case may be.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under any of the LGPL, the MPL or the GPL.
 */

#ifndef SKY_ENGINE_CORE_RENDERING_RENDERLAYERSTACKINGNODE_H_
#define SKY_ENGINE_CORE_RENDERING_RENDERLAYERSTACKINGNODE_H_

#include "flutter/sky/engine/core/rendering/RenderBox.h"
#include "flutter/sky/engine/wtf/Noncopyable.h"
#include "flutter/sky/engine/wtf/OwnPtr.h"
#include "flutter/sky/engine/wtf/Vector.h"

namespace blink {

class RenderLayer;
class RenderStyle;

class RenderLayerStackingNode {
  WTF_MAKE_NONCOPYABLE(RenderLayerStackingNode);

 public:
  explicit RenderLayerStackingNode(RenderLayer*);
  ~RenderLayerStackingNode();

  unsigned zIndex() const { return renderer()->style()->zIndex(); }

  // A stacking context is a layer that has a non-auto z-index.
  bool isStackingContext() const {
    return !renderer()->style()->hasAutoZIndex();
  }

  // Update our normal and z-index lists.
  void updateLayerListsIfNeeded();

  bool zOrderListsDirty() const { return m_zOrderListsDirty; }
  void dirtyZOrderLists();
  void updateZOrderLists();
  void clearZOrderLists();
  void dirtyStackingContextZOrderLists();

  bool hasPositiveZOrderList() const {
    return zOrderList() && zOrderList()->size();
  }

  // FIXME: should check for dirtiness here?
  bool isNormalFlowOnly() const { return m_isNormalFlowOnly; }
  void updateIsNormalFlowOnly();
  bool normalFlowListDirty() const { return m_normalFlowListDirty; }
  void dirtyNormalFlowList();

  void updateStackingNodesAfterStyleChange(const RenderStyle* oldStyle);

  RenderLayerStackingNode* ancestorStackingContextNode() const;

  // Gets the enclosing stacking context for this node, possibly the node
  // itself, if it is a stacking context.
  RenderLayerStackingNode* enclosingStackingContextNode() {
    return isStackingContext() ? this : ancestorStackingContextNode();
  }

  RenderLayer* layer() const { return m_layer; }

#if ENABLE(ASSERT)
  bool layerListMutationAllowed() const { return m_layerListMutationAllowed; }
  void setLayerListMutationAllowed(bool flag) {
    m_layerListMutationAllowed = flag;
  }
#endif

 private:
  friend class RenderLayerStackingNodeIterator;
  friend class RenderLayerStackingNodeReverseIterator;
  friend class RenderTreeAsText;

  Vector<RenderLayerStackingNode*>* zOrderList() const {
    ASSERT(!m_zOrderListsDirty);
    ASSERT(isStackingContext() || !m_zOrderList);
    return m_zOrderList.get();
  }

  Vector<RenderLayerStackingNode*>* normalFlowList() const {
    ASSERT(!m_normalFlowListDirty);
    return m_normalFlowList.get();
  }

  void rebuildZOrderLists();
  void collectLayers(OwnPtr<Vector<RenderLayerStackingNode*>>& zOrderList);

#if ENABLE(ASSERT)
  bool isInStackingParentZOrderLists() const;
  bool isInStackingParentNormalFlowList() const;
  void updateStackingParentForZOrderLists(
      RenderLayerStackingNode* stackingParent);
  void updateStackingParentForNormalFlowList(
      RenderLayerStackingNode* stackingParent);
  void setStackingParent(RenderLayerStackingNode* stackingParent) {
    m_stackingParent = stackingParent;
  }
#endif

  bool shouldBeNormalFlowOnly() const;

  void updateNormalFlowList();

  bool isDirtyStackingContext() const {
    return m_zOrderListsDirty && isStackingContext();
  }

  // FIXME: Investigate changing this to Renderbox.
  RenderBox* renderer() const;

  RenderLayer* m_layer;

  // m_zOrderList holds a sorted list of all the descendant nodes within
  // that have z-indices of 0 or greater (auto will count as 0).
  OwnPtr<Vector<RenderLayerStackingNode*>> m_zOrderList;

  // This list contains child nodes that cannot create stacking contexts.
  OwnPtr<Vector<RenderLayerStackingNode*>> m_normalFlowList;

  unsigned m_zOrderListsDirty : 1;
  unsigned m_normalFlowListDirty : 1;
  unsigned m_isNormalFlowOnly : 1;

#if ENABLE(ASSERT)
  unsigned m_layerListMutationAllowed : 1;
  RenderLayerStackingNode* m_stackingParent;
#endif
};

inline void RenderLayerStackingNode::clearZOrderLists() {
  ASSERT(!isStackingContext());

#if ENABLE(ASSERT)
  updateStackingParentForZOrderLists(0);
#endif

  m_zOrderList.clear();
}

inline void RenderLayerStackingNode::updateZOrderLists() {
  if (!m_zOrderListsDirty)
    return;

  if (!isStackingContext()) {
    clearZOrderLists();
    m_zOrderListsDirty = false;
    return;
  }

  rebuildZOrderLists();
}

#if ENABLE(ASSERT)
class LayerListMutationDetector {
 public:
  explicit LayerListMutationDetector(RenderLayerStackingNode* stackingNode)
      : m_stackingNode(stackingNode),
        m_previousMutationAllowedState(
            stackingNode->layerListMutationAllowed()) {
    m_stackingNode->setLayerListMutationAllowed(false);
  }

  ~LayerListMutationDetector() {
    m_stackingNode->setLayerListMutationAllowed(m_previousMutationAllowedState);
  }

 private:
  RenderLayerStackingNode* m_stackingNode;
  bool m_previousMutationAllowedState;
};
#endif

}  // namespace blink

#endif  // SKY_ENGINE_CORE_RENDERING_RENDERLAYERSTACKINGNODE_H_
